Fluid pressure regulator

ABSTRACT

A fluid pressure regulator for maintaining constant the downstream pressure at varying rates of flow has a chamber divided by a flexible diaphragm into two compartments one of which has an inlet and an outlet through which a first pressure fluid may flow under the control of a flow control valve, the position of the valve being determined by the position of the diaphragm and the position of the diaphragm being determined by the relative pressures of the first fluid and a second fluid in the other compartment of the chamber. The regulator is constructed in such manner as to prevent the accumulation therein of air entrained in the first fluid and the valve is capable of providing a bubble-tight shutoff for the regulator.

United States Patent [1 1 Clayton Oct. 2, 1973 FLUID PRESSURE REGULATORPrimary ExaminerArnold Rosenthal 7 l t Rh tW.CI t ,Pl th,M h. l 5] menor 0 er ay on ymou Att0rneyLearman & McCulloch [73] Assignee: ScansAssociates, Inc., Livonia,

Mich. [22] Filed: Apr. 30, 1971 [57] ABSTRACT [21] Appl' 138360 A fluidpressure regulator for maintaining constant the downstream pressure atvarying rates of flow has a [52] US. Cl. l37/505.35, 137/505.37,137/510, chamber divided by a flexible diaphragm into two com- 251/356partments one of which has an inlet and an outlet [51] Int. Cl. F16k31/12 hro gh which a first pressure fluid may flow under the [58] Fieldof Search l37/505.37, 505.35, control f a flow control valve, the p n ofh valve 137/5 l0, 87; 251/333, DIG. l, 364, 356, 61.3 being determinedby the position of the diaphragm and the position of the diaphragm beingdetermined by the [56] References Cited relative pressures of the firstfluid and a second fluid in UNITED STATES PATENTS the other compartmentof the chamber. The regulator is constructed in such manner as toprevent the accuh sff 22 mulation therein of air entrained in the firstfluid and 2360:1358 11/1958 gji: 3750537 the valve is capable ofproviding a bubble-tight shutoff 2,047,101 7/1936 Grove 137 505.37 forthe regulator- FORElGN PATENTS OR APPLICATIONS 11 Claims 5 DrawingFigures 925,165 3/1947 France 251/356 38 21 l5 l6 8 [Q 37 PILOT PRESSUREREGULATOR r 44 43 46 39 4o 6 l FLU) VOLUM TRIC 8 PRESSURE OR MAS FLOW 2MEASURING REGULATOR DEVICE II// 5:55;. Ill% \%fli F 7 'r v v r dnrahpwmFIG?) '24 I/ INVENTR ROBE RT W. CLAYTON ATTORNEYS FLUID PRESSUREREGULATOR The inventiondisclosed herein relates to a fluid regulatoradapted for use with either liquids or gases and which is capable ofmaintaining uniform the pressure of fluid discharged from the regulatorat varying rates of flow. More particularly, the invention comprises afluid regulator of the diaphragm type wherein the pressure of fluiddischarged from the regulator may be maintained within extremely closetolerances by the pressure of a second fluid acting on the diaphragm.

Fluid regulators of the kind disclosed herein are especially adapted foruse in systems such as those disclosed in US. Pat. Nos. 3,517,552 and3,524,344 for the testing and calibrating of carburetors, but the fluidregulators are useful in any system in which precision control overfluid pressure is desirable. If a fluid pressure regulator is to becapable of maintaining the pressure of fluid downstream from theregulator within extremely close tolerances, it must be capable ofresponding quickly and automatically to both large and small variationsin the pressure both upstream and downstream of the regulator. That is,the regulator must be responsive to both increases and decreases in thepressure of the influent and effluent fluid so as maintain virtuallyconstant the pressure of the effluent fluid.

Virtually all liquids include some absorbed air, the quantity of which,according to I-Ienry's Law, is proportional to the absolute pressure ofthe liquid. As liquid containing air is subjected to a reduced pressure,such as when the liquid passes a valve to a pressure regulator housing,the air has a tendency to separate from the liquid. If the air separatesfrom the liquid in the regulator, it can produce bubbles which,eventually, are discharged from the regulator resulting in extremelysharp pressure fluctuations which make it impossible to maintainconstant the pressure of liquid discharged from the regulator.

Among the objects of this invention is to provide a fluid regulatorwherein the flow of fluid through the regulator is under the direct andautomatic control of a valve which is operated in response to deflectionof a flexible diaphragm acted upon by a static pressure, the deflectionof the diaphragm being so related to the pressure of fluid admitted toand discharged from the regulator that for any given value of the staticpressure applied to the diaphragm the pressure of fluid discharged fromthe regulator is virtually constant.

Another object of the invention is to provide a fluid regulator whichprevents the accumulation of air in the regulator.

Another object of the invention is to provide a novel valve forcontrolling the flow of fluid through a fluid regulator and wherein thevalve is operable to assure a bubble-tight shutoff.

A further object of the invention is to provide a novel diaphragm foruse in a diaphragm-controlled fluid regulator and which is capable ofproviding a stable, regulated pressure over a wide range of varying flowand pressure conditions, including extremely low pressures.

Another object of the invention is to provide a fluid regulator which iscapable of accommodating greatly varying flow and pressure ranges withexcellent reproducibility.

Other objects and advantages of the invention will be pointed outspecifically or will become apparent from the following description whenit is considered in conjunction with the appended claims and theaccompanying drawings, in which:

FIG. 1 is a plan view of a regulator constructed according to oneembodiment of the invention;

FIG. 2 is a sectional view taken on the line 2-2 of FIG. 1;

FIG. 3 is a view similar to FIG. 2, but illustrating a modifiedembodiment;

FIG. 4 is an enlarged, fragmentary, sectional view of a valveincorporated in each of the embodiments shown in FIGS. 2 and 3; and

FIG. 5 is a schematic diagram illustrating the manner in which either ofthe fluid regulators may be incorporated in a typical fluid system.

A regulator constructed according to the invention comprises a housing 1having a body 2 and a cover 3 separably secured to one another by bolts4. The confronting surfaces of the body and the cover are recessed toform a chamber 5 which is divided into two compartments 6 and 7 by aflexible diaphragm 8. The diaphragm comprises a disc-like web 9 of wovenfabric such as nylon impregnated with a substance such as neoprene whichis impervious to gas and oil. The marginal edge of the web 9 isinterposed and sealed between the parts 2 and 3. Metal plates 10 of aflexible material such as aluminum are bonded to opposite sides of themember 9 for a purpose presently to be explained. At the center of thediaphragm is a shoulder screw 11 having a head 12 at one end and a nut13 threaded on its other end, the head and nut compressing sealsinterposed therebetween and the diaphragm.

At the center of the cover 3 is a port 14 which communicates with thecompartment 6. Except for the port 14 the compartment 6 is completelyclosed.

In axial alignment with the port 14 the body 2 has a bore 15 in which ismounted a guide bushing 16 and a valve sleeve 17 having an orifice orinlet 18 in communication with the compartment 7. Slidably accommodatedin the bushing 16 is a flow control member or valve body 19 having anose 20 at one end adapted to be accommodated in the bushing 17. The endof the sleeve 17 which confronts the nose 20 of the valve body 19 istapered'to form a seat 21 and the nose of the valve body is annularlygrooved as at 22 to receive a molded nipple 23 that is bonded to thevalve body. The nipple is formed of a rubbery, resilient material suchas neoprene that is impervious to oil and gas and preferably has adurometer hardness of between 45 and 55.

It is important that the valve seat 21 be concentric with the nipple 23and that the confronting surfaces of the seat and the nipple be smoothso as to avoid any leakage of fluid past the nipple when the latter isseated on the seat 21 and to avoid pressure fluctuations due to suchleakage. The bore 15, the bushing 16, the sleeve 17, the seat 21 and thenipple 23 all must be concentric, therefore, to enable such leakage tobe prevented.

At the outer end of the bore 15 is a closure plug 24 that is maintainedassembled with the body 2 by a retaining ring 25. A spring 26 reactsbetween the plug 24 and the valve body 19 and constantly urges thelatter toward sealing relation with the sleeve 17.

The body 2 has a pressure fluid inlet passage 27 which communicates withthe compartment 7 via the bore 15 and the inlet 18. The inlet passage 27has a branch 29 which establishes communication between the passage 27and the bore 15 at the outer end of the latter.

In the embodiment shown in FIG. 2, the body 2 has an outlet passage 29the inner end of which communicates with the compartment 7. A branch 30communicates at one end with the passage 29 and at the other endcommunicates with a passage 31 in the cover 3 via an opening 32 in thediaphragmmember 9. A passage 33 similar to the passage 31 alSo isprovided in the cover 3 at the opposite side of the latter, the innerend of the passage 33 communicating with a passage 34 in the body 2 viaan opening 35 in the diaphragm member 9. A vent port 36 establishescommunication between the compartment 7 and the passage 30 and a similarport 36a establishes communication between the compartment 7 and thepassage 34. The purpose of the ports will be explained hereinafter.

The valve body 19 has a right angle passage 37 therein whichcommunicates at one end with the inlet passage 27 and at the other endwith the branch passage 28 via the bore 15. The purpose of the passage37 also will be explained hereinafter.

Coupling the diaphragm 8 and the valve 19 is an actuating member 38comprising a rigid rod having its opposite ends freely accommodated inrecesses formed in the members 12 and 19, respectively. The length ofthe rod 38 is such that, when the diaphragm is in its normal ornon-deflected position, the inlet 18 of the sleeve 17 is sealed by thevalve body 19.

The embodiment of the invention shown in FIG. 3 is the same as theembodiment shown in FIG. 2 except that the embodiment of FIG. 3 does notinclude the parts 30, 31, 32, and 36. In all other respects, however,the two embodiments are identical and corresponding reference charactersdesignate corresponding parts.

Apparatus constructed according to either embodiment of the invention isadapted to be installed in a system diagrammatically disclosed in FIG.5. The fluid pressure regulator housing 1 is adapted to have its inlet27 connected to a tube 39 through which either a liquid or a gas may bedelivered from a source (not shown) thereof under pressure. The outlet29 of the housing 1 may be connected by a tube 40 to the inlet of adevice 41 of known construction, such as a volumetric or mass flowdevice, the outlet of which may be connected by a tube 42 to acarburetor (not shown) to be tested or calibrated or to any othersuitable device. The passage 14 of the housing 1 is adapted to beconnected by a tube 43 to a second source (not shown) of pressure fluidwhich may be either a liquid or a gas. The tube 43 will include aconventional fitting (not shown) by means of which the compartment 6 maybe purged of air. A pilot pressure regulator 44 of known construction ispositioned in the tube 43 for controlling the pressure of the pilotfluid delivered through the tube 43 to the compartment 6 of the housing1.

When the apparatus is installed in a system in the manner indicated inFIG. 5, it may be conditioned for operation by admitting fluid from thesource of pilot fluid to the compartment 6 under such pressure as toovercome the force of the spring 26 and cause deflection of thediaphragm 8 to the right, as viewed in FIG. 2, whereupon the valveactuator rod 38 will displace the valve body 19 to the right so as toestablish communication between the passage 27 and the compartment 7 viathe inlet 18. As the fluid to be controlled enters the passage 27 fromthe source of such fluid, some of the fluid will flow immediately intothe compartment 7 and some of the fluid will flow through the passage 28into the outer end of the bore 15 and thence through the passage 37 soas to purge air from the bore 15. Fluid which enters the compartment 7will fill the latter and drive any air in the compartment through theports 36 and 360 so as to purge the compartment. Thereafter, plugs 45and 46 may be fitted into the passages 31 and 33, respectively, so as toseal the latter, whereupon fluid may flow from the compartment 7 onlythrough the outlet 29. It will be understood, however, that the outlet29 could be closed by a plug (not shown) and the plug 45 omitted,whereupon fluid will flow from the compartment 7 through the branchoutlet passage 30. The passages 29 and 30 are of different diameters soas to provide for different maximum rates of fluid flow through theregulator.

The position of the valve body 19 depends upon the amount of deflectionof the diaphragm 8 and the amount of deflection of the diaphragm dependsupon the pressure of fluid in the compartment 6 and the pressure offluid in the compartment 7. The fluid pressure in the compartment 6 mustbe sufficient, of course, to overcome the force of the spring 26 so asto effect opening of the valve in the first instance. Once the valve isopen, the pressure of fluid admitted to the compartment 7 will act inopposition to the pressure in the compartment 6 until such time as acondition of equilibrium exists. When such equilibrium is reached, arate of flow of fluid through the regulator housing 1 at a desiredpressure will be established.

When the fluid flow through the regulator housing 1 is established, anyincrease in the pressure of fluid in the compartment 7, such as may becaused by a surge upstream of the regulator or by a fluid flow reductiondownstream of the regulator, will cause the diaphragm 8 to be deflectedto the left, as viewed in FIGS. 2 and 3. The spring 26 will cause acorresponding movement of the valve 19 and effect a partial closing ofthe inlet 18, thereby decreasing the quantity of fluid admitted to thecompartment 7 and preventing an increase in the pressure of the fluiddischarged from the compartment 7. Conversely, a decrease in thepressure of fluid in the compartment 7, caused by pressure reductioneither upstream or downstream from the regulator, will enable thepressure of the pilot fluid in the compartment 6 to displace thediaphragm 8 to the right, as viewed in FIGS. 2 and 3, so as to cause acorresponding movement of the valve 19 and increase the quantity tofluid admitted to the compartment 7, thereby preventing a reduction inthe pressure of fluid discharged from the compartment 7.

In the event the pressure of the pilot fluid in the compartment 6 shouldfail, the pressure of fluid in the compartment 7 will displace thediaphragm 8 to the left, as viewed in FIGS. 2 and 3, thereby enablingthe spring 26 to move the valve 19 onto its seat 21 and terminate theflow of fluid through the regulator. The resilient nipple 23 willprovide a completely tight, bubble-free seal with the valve seat 21 soas to prevent any leakage of fluid past the valve. Consequently, noadditional shut-off valve is required.

The pilot fluid which is introduced to the compartment 6 may be either agas or a liquid, the pressure of which may be maintained virtuallyconstant by the pilot pressure regulator 44. The fluid which passesthrough the regulator housing 1 also may be either a gas or a liquid. Ifsuch fluid is a liquid, it is almost certain to con tain a quantity ofabsorbed air or other gas which has a tendency to separate from thefluid as it passes through the regulator, inasmuch as there inevitablywill be pressure drop across the regulator. Any irregular surfaces inthe body 2 thus may form pockets in which airmay accumulate until suchtime as a bubble exists which is sufficiently large to be washed out ofthe regulator by fluid flowing therethrough. The various ports andpassages and the compartment 7 should have smooth surfaces so as toprevent the formation of pockets in which air can accumulate.

The passages 28 and 37 act not only to purge air from the outer end ofthe valve body 19, but also to prevent the accumulation behind the valveof air which may be released from the fluid. The presence of air at theouter end of the valve is objectionable because movement of the valveinwardly would be opposed by suction, and movement of the valveoutwardly would be opposed by compression of the air. The passages 28and 37 permit any air bubbles which may tend to accumulate behind thevalve to be washed out by fluid flowing through these passages, therebymaking it possible for the position of the valve to be responsive solelyto differential pressures in the compartments 6 and 7 and the spring 26.lt thus is relatively easy to calibrate the pressure which must bemaintained in the compartment 6 to maintain a flow of fluid through theregulator such as to establish and maintain a desired pressure-of theeffluent fluid. The ratio of the two pressures may be one to one, isdesired.

As has been stated hereinbcfore, the diaphragm member 9 preferablycomprises a web woven from fabric such as nylon and impregnated withneoprene. The fabric has some elasticity in the directions of the woofand warp fibers, but such elasticity is considerably less that thatpossessed by the fabric in directions diagonally of the warp and wooffibers. Since the chamber 5 is circular, the diaphragm 8 also must becircular and, consequently, deflection of the diaphragm causes forces tobe exerted on the member 9, some of which forces are diagonal of thewarp and woof fibers. Since the member 9 has greater elasticity in thediagonal directions, it is possible that the member 9 could becomedistorted and form pockets for the reception and accumulation of airreleased from a liquid. It is to overcome the tendency of the member 9to distort that the metal plates 10 are provided, and the area of theplates 10 should be only sufficiently less than the area of the member 9to assure substantially instantaneous deflection of the diaphragm inresponse to slight changes in differential pressures on opposite sidesof the diaphragm. Thus, if the diameter of the chamber 5 is 6 inches,for example, the diameter of the plates 10 may be 5' inches, therebyproviding an annular space of onehalf inch around the plates. Thedistortion of which the member 9 is capable thus is minimized to avirtually insignificant amount.

The construction of the sealing nipple 23 is an important characteristicof the invention. As is shown in FIG. 4, the nipple 23 has a generallytear-drop shape in cross-section and is bonded in the groove 22. Theshape and bonding of the nipple prevent it from vibrating, as oftenhappens with conventional O-rings, and also avoids elastic rebound suchas occurs with O-rings. The bonding of the nipple also precludes itsbeing stripped or blown off the valve in the event of an unusually largepressure change.

The regulators disclosed herein may be mounted directly in the fluidline extending from the fluid source to the flow measuring device, isdesired. Alternatively, the regulators may be mounted on a stand bymeans of a bracket 47 which may be fixed to the housing 1 by two or moreof the bolts 4. lf the regulator is mounted on a stand, the fluid lines,of course, will have to be arranged in such manner as to lead to andfrom the housing.

Due to the ability of the diaphragm 8 to respond substantiallyinstantaneously to any change in differential pressures on oppositesides of the diaphragm and thereby effect a substantially instantaneousadjustment of the valve 19, and due to the prevention of theaccumulation of air bubbles in the regulator, the pressure of the fluiddischarged from the pressure regulator may be maintained extremelystable, thereby enabling the regulator to be particularly well suitedfor utilization in testing and calibrating carburetors or any otherdevice wherein the pressure of a fluid delivered to such a device mustbe maintained within close tolerances over large variations in flowranges.

The disclosed embodiments are representative of the presently preferredforms of the invention, but are intended to be illustrative rather thandefinitive thereof. The invention is defined in the claims.

What is claimed is:

l. Fluid pressure regulating apparatus comprising a housing having achamber therein; flexible diaphragm means dividing said chamber into twoopposed compartments; means for establishing a first pressure in one ofsaid compartments; a bore in said housing establishing at one endthereof an inlet to the other of said compartments; means sealing theother end of said bore; a fluid passage communicating with said bore forintroducing a pressure fluid via said inlet to the other of saidcompartments to establish a second pressure therein opposing said firstpressure; first passage means in said housing separate from said fluidpassage and said bore having one end thereof communicating with saidfluid passage and having its other end communicating with said boreadjacent the sealed end thereof; a valve member slidably mounted in saidbore and movable in opposite directions to open and close said inlet;spring means acting on said valve member and urging the latter in adirection to close said inlet; valve actuating means coupling saiddiaphragm means and said valve member and operable in response to anincrease in said first pressure relative to said second pressure to movesaid valve member in a direction to open said inlet; second passagemeans establishing communication between said fluid passage and saidother end of said bore; and outlet means communicating with said othercompartment for discharging fluid therefrom.

2. Apparatus according to claim 1 wherein said valve means comprises abody having a nose adapted to seal and unseal said inlet.

3. Apparatus according to claim 2 wherein said nose carries a resilientmember adapted to seat on the edges of said inlet.

4. Apparatus according to claim 3 wherein said resilient member isfitted in a groove in said nose and is bonded thereto.

5. Apparatus according to claim 4 wherein said resilient member has asubstantially tear drop shape in cross-section.

6. Apparatus according to claim 1 including normally closed ports insaid housing for venting said second compartment and means forselectively opening and closing said ports.

7. Apparatus according to claim 1 wherein said diaphragm means comprisesa flexible fabric having an area corresponding to the area of saidchamber, and at least one flexible metal member bonded concentrically tosaid fabric and having an area less than that of said fabric.

8. Apparatus according to claim 1 wherein said second passage means isin said valve member.

9. Fluid pressure regulating apparatus comprising a housing having achamber therein; flexible diaphragm means dividing said chamber into twoopposed compartments; means for establishing a first pressure in one ofsaid compartments; a bore in said housing establishing at one endthereof an inlet to the other of said compartments; means sealing theother end of said bore; a fluid passage communicating with said inletfor introducing a pressure fluid via said inlet to the other of saidcompartments to establish a second pressure therein opposing said firstpressure; passage means establishing communication between said fluidpassage and said bore adjacent the sealed end thereof; a valve memberslidably mounted in said bore and movable in opposite direction to openand close said inlet; spring'means acting on said valve member andurging the latter in a direction to close said inlet; valve actuatingmeans coupling said diaphragm means and said valve member and operablein response to an increase in said first pressure relative to saidsecond pressure to move said valve member in a direction to open saidinlet; and outlet means communicating with said other compartment fordischarging fluid therefrom, said passage means comprising a branchcommunicating with said bore adjacent said sealed end thereof, andwherein said valve member has a passage therein establishingcommunication between said fluid passage and said branch.

10. Apparatus according to claim 9 wherein said valve member has a noseadapted to seat on said inlet, said nose including a resilient sealingmember concentric with said valve member and with said inlet.

11. Apparatus according to claim 10 wherein said resilient sealingmember is bonded to said valve member.

1. Fluid pressure regulating apparatus comprising a housing having achamber therein; flexible diaphragm means dividing said chamber into twoopposed compartments; means for establishing a first pressure in one ofsaid compartments; a bore in said housing establishing at one endthereof an inlet to the other of said compartments; means sealing theother end of said bore; a fluid passage communicating with said bore forintroducing a pressure fluid via said inlet to the other of saidcompartments to establish a second pressure therein opposing said firstpressure; first passage means in said housing separate from said fluidpassage and said bore having one end thereof communicating with saidfluid passage and having its other end communicating with said boreadjacent the sealed end thereof; a valve member slidably mounted in saidbore and movable in opposite directions to open and close said inlet;spring means acting on said valve member and urging the latter in adirection to close said inlet; valve actuating means coupling saiddiaphragm means and said valve member and operable in response to anincrease in said first pressure relative to said second pressure to movesaid valve member in a direction to open said inlet; second passagemeans establishing communication between said fluid passage and saidother end of said bore; and outlet means communicating with said othercompartment for discharging fluid therefrom.
 2. Apparatus according toclaim 1 wherein said valve means comprises a body having a nose adaptedto seal and unseal said inlet.
 3. Apparatus according to claim 2 whereinsaid nose carries a resilient member adapted to seat on the edges ofsaid inlet.
 4. Apparatus according to claim 3 wherein said resilientmember is fitted in a groove in said nose and is bonded thereto. 5.Apparatus according to claim 4 wherein said resilient member has asubstantially tear drop shape in cross-section.
 6. Apparatus accordingto claim 1 including normally closed ports in said housing for ventingsaid second compartment and means for selectively opening and closingsaid ports.
 7. Apparatus according to claim 1 wherein said diaphragmmeans comprises a flexible fabric having an area corresponding to thearea of said chamber, and at least one flexible metal member bondedconcentrically to said fabric and having an area less than that of saidfabric.
 8. Apparatus according to claim 1 wherein said second passagemeans is in said valve member.
 9. Fluid pressure regulating apparatuscomprising a housing having a chamber therein; flexible diaphragm meansdividing said chamber into two opposed compartments; means forestablishing a first pressure in one of said compartments; a bore insaid housing establishing at one end thereof an inlet to the other ofsaid compartments; means sealing the other end of said bore; a fluidpassage communicating with said inlet for introducing a pressure fluidvia said inlet to the other of said compartments to establish a secondpressure therein opposing said first pressure; passage meansestablishing communication between said fluid passage and said boreadjacent the sealed end thereof; a valve member slidably mounted in saidbore and movable in opposite direction to open and close said inlet;spring means acting on said valve member and urging the latter in adirection to close said inlet; valve actuating means coupling saiddiaphragm means and said valve member and operable in response to anincrease in said first pressure relative to said second pressure to movesaid valve member in a direction to open said inlet; and outlet meanscommunicating with said other compartment for discharging fluidtherefrom, said passage means comprising a branch communicating withsaid bore adjacent said sealed end thereof, and wherein said valvemember has a passage therein establishing communication between saidfluid passage and said branch.
 10. Apparatus according to claim 9wherein said valVe member has a nose adapted to seat on said inlet, saidnose including a resilient sealing member concentric with said valvemember and with said inlet.
 11. Apparatus according to claim 10 whereinsaid resilient sealing member is bonded to said valve member.